Final answer:
Rats easily learn to associate a taste with feeling nauseous due to classical conditioning, according to Garcia's studies.
Step-by-step explanation:
The studies of Garcia and his colleagues show that rats easily learn to associate a taste with a nausea-inducing unconditioned stimulus (US). This is called taste aversion and it is a form of classical conditioning. Rats quickly learn to avoid a taste that is followed by feeling nauseous, which is a helpful adaptation to avoid harmful foods.